[PATCH v3 09/24] ewah: add bitmap_dup() function

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From: Jeff King <peff@xxxxxxxx>

There's no easy way to make a copy of a bitmap. Obviously a caller can
iterate over the bits and set them one by one in a new bitmap, but we
can go much faster by copying whole words with memcpy().

Signed-off-by: Jeff King <peff@xxxxxxxx>
Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
---
 ewah/bitmap.c | 7 +++++++
 ewah/ewok.h   | 1 +
 2 files changed, 8 insertions(+)

diff --git a/ewah/bitmap.c b/ewah/bitmap.c
index 0a3502603f..b5f6376282 100644
--- a/ewah/bitmap.c
+++ b/ewah/bitmap.c
@@ -35,6 +35,13 @@ struct bitmap *bitmap_new(void)
 	return bitmap_word_alloc(32);
 }
 
+struct bitmap *bitmap_dup(const struct bitmap *src)
+{
+	struct bitmap *dst = bitmap_word_alloc(src->word_alloc);
+	COPY_ARRAY(dst->words, src->words, src->word_alloc);
+	return dst;
+}
+
 static void bitmap_grow(struct bitmap *self, size_t word_alloc)
 {
 	size_t old_size = self->word_alloc;
diff --git a/ewah/ewok.h b/ewah/ewok.h
index 011852bef1..1fc555e672 100644
--- a/ewah/ewok.h
+++ b/ewah/ewok.h
@@ -173,6 +173,7 @@ struct bitmap {
 
 struct bitmap *bitmap_new(void);
 struct bitmap *bitmap_word_alloc(size_t word_alloc);
+struct bitmap *bitmap_dup(const struct bitmap *src);
 void bitmap_set(struct bitmap *self, size_t pos);
 void bitmap_unset(struct bitmap *self, size_t pos);
 int bitmap_get(struct bitmap *self, size_t pos);
-- 
2.29.2.533.g07db1f5344




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